Insulation cutting tool



1-945. J. N. ROLLINGS INSULATION CUTTING TOOL Filed March 27, 1943 -INVENTOR. .1 ME LLINGS Patented Oct. 9, 1945 7 2,386,323 INSULATION CUTTING TOOL" J ,James N. Rollings, Baltimore Md assignor to Western Electric Company, Incorporated; New York, N. Y., a corporation of New York Application March 27, 1943, serial'nansogsisi 2Claims. I (01. 81-9.5-)

This invention relates to: insulation cutting tools andmore particularly to tools for stripping predetermined lengths of insulation from cable cores.

In preparing a multiconductor cable to be 'attached to the terminals of a connecting plug, or other electrical device, the insulating jacket surrounding the group of conductors forming the core is remove'd for a predetermined distance from the end of the cable and then portions of the insulation on the individual insulated conductors are removed from the ends of the conductors for a predetermined distance to bare the desired amount of the conductors. The insulation employed in such cables'may be a tough,

elastic, vulcanized rubber composition or other tough plastic materials.

In removing the insulation from the individual conductors, the lengths of the insulation removed therefrom should be uniform. Previously the amount of insulation removed depended upon the judgment of the operator and thus was subject to errors. If the length to be stripped were measured in each case, this operation required too much attention and time of the operator.

It is an object of this invention to provide new and improved insulation cutting tools.

The particular embodiment of the invention described herein comprises a tool resembling pliers provided with a pair of crossed pivoted members having cutting blades removably attached, each of which blades has an arcuate cutting edge, straight cutting edges and abutments formed thereon, and a gauge adjustably attached to one of the crossed member to permit an insulated conductor to be inserted between the cutting blades only a predetermined distance from the gauge.

The invention may be fully understood from the following description, taken in conjunction with the accompanying drawing, .in which Fig. 1 is a perspective view of a cutting tool embodying the invention;

Fig. 2 is a fragmentary side elevation thereof;

Fig. 3 is a fragmentary sectional view thereof taken along the line 3-3 in Fig. 2, and

Fig. 4 is a plan view of a portion ofthe tool.

Referring to Fig. 30f the drawing, a jaw I!) having a semicylindrical groove I I therein is formed on one end of a lever l2 having a handle l3 at the opposite end thereof. A cutting blade l4, removably secured by screws [6-46 in a socket formed in the top end of the jaw H), has abutments lll1 (Fig. 4) projecting slightly beyond straight cutting edges l8| 8 and an contacting each other.

arcuate cutting edge l9 formed thereon. An

L-shaped gauge 20- is adjustably secured to, the jaw H) by screws 22+22 extending through an elongated. slot 2| formed therein. The gauge 20 has an arcuate surface 23* formed at onesi'de of a transverse arm- 2'5 thereon to permit an individu-ally' insulated conductor 25 to pass betweent'he-jaw 1c and a companion jaw 26 formed at one end of a leverZ'l having a handle 28 at the opposite end thereof.

The jaw 26 projects transversely from the lever 21 and has a" semicylindri'calgroove 29 therein opposite the groove II in: the jaw Ill. A'cutting blade 33, removably secured by screws 31-4]: in a socket 32 "formed. in the jaw 26; has formed thereon abut'merits 35-35: projecting slightly beyondstrai'ght' cutting edges 33---33 and an arouate cutting edge 34 similarto-those'on the blade M. Theilevers I 2 and Rare pivotallyconnected tya-pmas; sothat when'thehandles l3 and 28 are 'nioved' inward-ly'the abutments l"! and35 are brought into contact with each other and prevent the cutting edges I8l8 and 3333 from However, the clearance between these cutting edges is very slight and is insufiicient to prevent them from cutting and stripping insulation satisfactorily.

To prepare the end of a cable 38 (Fig. 1) for connection to a cable plug or other electrical device. an outer insulating jacket 31, composed of a vulcanized rubber composition or the like, is severed to form a shoulder 39, and the severed portion of the jacket 31 is removed from the individually insulated conductors 25 and 40. The individual conductors 25 and 40 comprise insulating coverings 42 and 43 made'of a vulcanized rubber compound, or similar material, surrounding conducting cores, such as the stranded conductor 44. In order to affix a connecting plug to the end of a cable of this construction, it is desirable to havethe insulation stripped from the individual conductors for a given distance from the ends of the conductors and also to have predetermined lengths of the insulated conductors between the stripped portions of the conductors and the shoulder 39 formed on the outer jacket 31 when the jacket is stripped from the free ends of the insulated conductors. The appearance of the finished ends of the stripped conductors is illustrated b the conductor 40 (Fig. 1).

To make the conductor 25 correspond to the stripped conductor 40, the gauge 20 is first adjusted to the position desired and secured by the screws 2222. The cable 38 is then positioned edges I9 and 34 to cut through the insulation 3 42 to the conductor therebeneath. The cutting tool is then rotated about the conductor 25 m completely sever the insulation, whereupon,the

severed portion of the insulationmay be stripped l5 s. ably secured to the jaws an having arcuate cutfrom the conductor 25 by drawing the toolaway from the free end of the conductor. The cutting edges l8-l8 and 3333 are prevented from contacting and thus injuring each other, by the projecting abutments 7 -11 and 35-45, although the clearance between the cutting edges is so slight as to be almost unnoticeable.

This operation is facilitated by the gripping action of the grooves II and 29 upon the severed portion of the insulation 42 which protrudes therebetween. Since the arcuate cutting edges [9 and 34 coact to form a substantially circular opening, the diameter of which is just about the same as that of the conductor, the conductor is not injured when the insulation is severed.

' "Obviously, with the gauge set in a given position, all lengths of the bared conductors will bejuniform. If diflerent'lengths of the conductors are desired to be bared, the screws 22-'-22 jaws having complementary and 3l--3L When it is desired to strip the insulation from a conductor of a different diameter, the blades I4 and 30 may be removed and replaced with blades having arcuate cutting edges l9 and 34 conforming to the diameter of this conductor.

It will be understood that modifications may be made in the. herein described embodiment of the invention without departing fromithe spirit and scope of the invention, which are limited only by the appended claims.

What is claimed is: a '1'. A' wire stripping tool comprising a pair of jaws having complementary semicylindrical grooves therein, a pair of stripping blades removting edges thereon, and a gauge having a transverse arm provided with an arcuate out out portion positioned outwardly from the blades, which gauge is adjustably secured to one of the jaws so that the arm projects a predetermined distance beyond the cutting blades for severing a predetermined length of insulation from a conductor inserted between the jaws and against the gauge.

2; A- wire stripping tool comprising a pair of semicyiindrical grooves therein, a-pair of stripping blades removablysecured to the jaws and having contiguous,

arcuate and straight cutting edges-thereon and abutments thereon to prevent the straight cutting edges from striking'each other, and a gauge having a transverse arm provided with an arcuate cut out portion positioned outwardly from the blades, which gauge is adjustably secured to one of the jaws'so that the arm projects a predetermined distance beyond the cutting blades for severing a predetermined length of insulation from a conductor insertedbetween the jaws and against the gauge.

- JAMES N. ROLLINGS. 

